Vaporizing burner with temperature regulated mixer to control flame heating of retort



3,097,687 XER VAPORIZING BURNER WITH TEMPERATURE REGULATED MI TO CONTROL FLAME HEATING 0F RETORT Filed March 30, 1959 July 16, 1963 77 W YFM ATTORNEYS Rn mm m MP B V.. a R on L mm m W 5H ,|I|| Q R Q m. mm United States Patent Office 3,697,687 Patented July 16, 1963 3 097,687 VAPORIZING BURNER WITH TEMPERATURE REGULATED MIXER T CONTROL FLAME HEATING OF RETORT Ray B. Fanniu, Denver, Colo., assignor to Gas Engineer ing & Equipment Co., Denver, Colo., a corporation of Colorado Filed Mar. 30, 1959, Ser. No. 803,022 2 Claims. (Cl. 158-79) This invention relates to gaseous fuel burners and more particularly to burners utilizing butane and propane as a fuel.

In many industrial applications it is necessary or advantageous to have portable heaters or furnaces which can be easily moved from one operating site to another without difficult dismantling and reassembling. As an example, in highway construction it is necessary to heat certain materials, such as black-top for example, and to apply and work the same at prescribed temperatures. As much of this work has to be performed at rather low ambient temperatures, it is not practical to transport the heated material for long distances or for long time intervals due to the resulting temperature drop in the material.

7 Where portable burners or furnaces are used in heating such materials, many of the operating sites will be remote from the usual sources of fuel supply. However, adequate supply for distribution of butane and propane fuels is available to permit use of one or the other 'as. the fuel in such heaters or furnaces. This involves storage of a considerable supply of such a composition in its liquid form together with means. for supplying it to a burner which preferably is utilized as the heat source to convert it into a gaseous or vapor form prior to its discharge into the combustion area of the furnace or other heater.

A typical portable plant \of this type will have a fuel storage tank comprising a main supply for the furnace and another tank, usually designated nurse tank, for maintaining the desired pressure condition in the storage tank. If butane is being used, it .will have a boiling point of 32.. F. and it will be necessary to maintain it within a pressure range of 100 to 125 pounds in the storage tank which may be subjected to atmospheric temperatures of from -l0 to 100 F. The vapor on top of the nurse tank is conducted to the storage tank to maintain at least a minimum pressure therein at all times. A line will supply the fuel burner assembly of the furnace with fuel from the storage tank and, so long as the minimum pressure condition is maintained, there is very little need to make any discharge nozzle adjustment in the practice of the present invention.

It also has been customary to provide a burner assembly in which a stretch of pipe conducting the liquid is coiled or otherwise wound as an enclosure adjacent the discharge nozzle and within the range of flame propagation so that the coil is substantiallyheated while the burner is operating and thus converts the liquid phase to a gaseous phase prior to discharge. Usually such structure is housed within a hollow member or shell having a tubular member at one end functioning as a mixer to supply available oxygen, usually air, for mixing with the fuel discharge to provide an efiicient mixture to support combustion. Whenever the operator observes differences infurnace temperature due to fluctuating feed rate, he changes the valve setting to deliver more or less fuel, thereby changing flame propagation with excessive heating of certain areas of the mixer or the furnace. Th1s present practice involves operator observance and udgment of conditions for manual adjustment and usually does not establish the optimum combustion condition.

Accordingly, it is an object of my invention to provide a simple, durable and efficient control of a burner for butane or propane which is adjusted in accordance with prevailing temperatures in the burner to maintain 5 optimum flame propagation and heating in continuous operation.

Another object of my invention is to provide an automatic control, inclusive of a temperature responsive member for selectively positioning the casing of a fuel mixer relative to its nozzle to maintain substantially optimum flame propagation in a burner assembly during continuous operation.

A further object of my invention is to provide a simple, durable and efiicient fuel burner for portable furnaces which is easily installed and dismantled for maintenance lowing description.

The present invention represents a departure from prior practices in that the hunting adjustments of fuel delivery rate to meet changing furnace requirements are eliminated. Measurements of temperature change within the furnace requiring variation in the heat input are indicated on a temperature responsive instrument with mechanical ad ustment, either automatic or under manual control, being made in the flame propagation so as to maintain optimum combustion within the furnace in continuous operation. The extent of heating of the fuel in the coil portion will deliver the fuel as substantially volatile matter at the point of discharge. Any non-volatiles passing the nozzle are discharged through the coil at sufficiently high velocity to carry beyond the outermost coil surfaces. In addition the direction of the flame relative to the coil produces a scouring action which will effectively remove any deposit thereon so as to maintain the metallic surfaces at maximum heat exchange condition.

The aforesaid adjustment is provided for by a telescop- 49 ing arrangement of members constituting the fuel-air mixer and involves lengthening and shortening of the tubular enclosure according to the rate at which fuel is being delivered. in this way a focusing effect in the flame propagation is avoided and all surfaces of the coil assembly are heated adequately without any excessive heating of particular areas. In addition, the practice of the present invention provides measured adjustments of the mixer to maintain optimum heat input by the burner so that the furnace temperature is closely controlled throughout a long period of heating.

The practice of my invention will be best understood by reference to the accompanying drawings, illustrating prefer-red structural embodiments for satisfying the requirements of this invention. In the drawings,

The single FIGURE is a vertical central section through a burner assembly according to the present invention, inclusive of an automatic control of the fuel mixer operation, and illustrating the manner of its assembly and installation as the heat source of a heater, such as a furnace for heating aggregate to proper temperature for highway installation.

The form of the invention shown includes a shell or housing '12 supported as shown at 13 from a base or foundation 14 which may be a wall of a furnace (not shown). A line 15 for supplying butane or propane under pressure has a portion wound as a coil 16 which extends into an opening 17 in housing 12 and the opposite end of coil 16 has a straight extension 18 passing out of the rear end of shell 12. carrying a temperature-recording instrument 7, with a branch line 20 extending from extension 18 through T-coupling 19 toward coil 16 in concentric relation thereto and having a mixing nozzle 21. at its end through which the gaseous product passing from coil 16 into branch 20 is discharged in conical formation into a fuel-air mixer. The line 15 may be provided with a quick coupling fitting 22 and a valve 23 permits shut-off and opening as required. A similar fitting 22a is provided at the end of extension 18.

A spider assembly 24 is supported at the rear of housing 12 by arm portions 24a adjustably held in guides 25 mounted on the exterior of housing 12 and secured in selective positions by set screws 26. A tubular member 27 forming a portion of the fuel-air mixer is fastened to spider 24 and encompasses nozzle 21 in concentric relation and extends forwardly into the end of housing 12' and terminates in spaced relation to the end of coil 16. Another tubular member 2.7a also constituting a portion of the fuel-air mixer is mounted on member 27 in telescoping relation at its forward end and is secured to a rod 28 carried on a lever 29 having a base pivot 30 and an associated stop member 3-1 and a scale (not shown) indicating lever setting positions in relation to temperature readings on instrument 7.

In operation, line 15 will be connected with a storage tank of the type previously described, which supplies butane or propane under at least a minimum established pressure suflicient to deliver the liquid through line 15 and into the coil 16 at a substantially uniform volume and velocity. Valve 23 is moved to open position when the operation begins, and the spider setting is established for the prevailing temperature of the furnace operation. The position of member 27a relative to member 27 is set by a scale adjacent stop 31 for the initial heating to pre scribed maximum temperature in the furnace, after which it is adjusted according to the indicated requirements of instrument 7.

The effective length of the mixer comprising the members 27 and 27a determines the length and pattern of flame propagation and will be extended during low velocity supply to direct the flame away from rear surfaces of coil 16 to surfaces further forward and thus provide a better distribution of heat input to the coil. As the volume increases, due either to more eifective heating in coil 16 or increased pressure in the supply tank, the mixer may be shortened to permit the flame to impinge on all exposed areas of coil 16.

The form of the invention shown has mechanism for automatic adjustment of the fuel mixer settings. As used herein, the term mixer is applied to housing members 27 and 27a. The nozzle 21 has one or a series of passages directing the gaseous discharge in a conical pattern, and the open rear end of tubular member 27 admits the primary air supply for mixing with the gas to provide the proper mixture for supporting combustion. The entire assembly including the encased coil 16 and the mixer comprises the burner, from which the flame or products of combustion, together with the secondary air supply which enters the open rear end of the burner exteriorly of the mixer are directed into the furnace or other heater in which the burner is mounted.

The automatic control assembly includes a line 35 fitted in member 19 and connected with a bellows 36 which is expanded and contracted in response to measure temperature increases and decreases by a thermometer 7 or other temperature-sensitive device in member 19', which directs a fluid at different pressures through line 35 into bellows 36 in response to such changes. A rod 37 supported for lengthwise movement in bearings 38 is connected with the end of bellows 36 and preferably is a twopart member with interconnected right and left hand threads so as to permit variation of the effective length of rod 37 in the initial setting of the mixer housing members. The extended end of rod 37 bears against lever 29 to move the rod 28 in adjusting the telescoping members comprising the mixer housing. A spring 40 is positioned to resist forward movement of lever 29 and direct its return with rod 37 when the bellows contracts after pressure in line 35 is reduced.

From the foregoing, it will be apparent that the present invention provides a manual control with predetermined adjustments for start up and an automatic control for continuous operation providing a selective adjustment of the mixing of fuel with primary air and its discharge into a burner with controlled flame propagation to maintain optimum combustion within a furnace with which such burner is associated.

The practice of this invention permits use of a temperature-indicating scale with the various adjustment positions of the fuel-air mixer so as to establish and maintain optimum heating within a furnace or other heater with which such mixer and burner is associated. Such adjustments distribute the flame over the encased coil section in such a way that excessive heating of any given coil area is avoided and a uniform fuel delivery rate to v the nozzle is maintained.

I claim:

1. In a fuel burner assembly, a burner housing open at both ends, a line for connection with a source of butane or propane maintained under pressure and including a coiled portion disposed interiorly of said burner housing and an extension portion supported rearwardly of said housing, a temperature-sensitive instrument mounted in said extension portion, a fuel-air mixer mounted at the rear of said housing with a forward portion in the housing and including telescoping tubular members open at both ends, a branch conduit for receiving the gaseous discharge of the extension portion and carrying a forwardly-directed discharge nozzle extending into the rear end of the .telescoping members, and means including a pressure-actuated member responsive to measured temperature variations for changing the elfective combined length of said telescoping members so as to vary flame impingement on said coil.

2. In a fuel burner assembly, a burner housing open at both ends, a line for connection with a source of butane or propane maintained under pressure and including a coiled portion disposed interiorly of said burner housing and an extension portion supported rearwardly of said housing, a temperature-sensitive instrument mounted in said extension portion, a fuel-air mixer mounted at the rear of said housing with a forward portion in the housing and including telescoping tubular members open at both ends, a branch conduit for receiving the gaseous discharge of the extension portion and carrying a forwardly-directed discharge nozzle extending into the rear end of the telescoping members, and means cooperating with said instrument and automatically movable in accordance with measured temperature changes of said instrument .to telescope said mixer members and vary the effective length thereof, thereby controlling flame pattern within the burner.

References Cited in the file of this patent UNITED STATES PATENTS 752,137 White Feb. 16, 1904 2,111,239 Elze Mar. '15, "1938 2,250,903 Browning July 29, 1941 2,467,450 Wollner Apr. 19, 1949 2,693,229 Pagan Nov. 2, 1954- 2,935,l26 Kaczenski May 3, 1960 

1. IN A FUEL BURNER ASSEMBLY, A BURNER HOUSING OPEN AT BOTH ENDS, A LINE FOR CONNECTION WITH A SOURCE OF BUTANE OR PROPANE MAINTAINED UNDER PRESSURE AND INCLUDING A COILED PORTION DISPOSED INTERIORLY OF SAID BURNER HOUSING AND AN EXTENSION PORTION SUPPORTED REARWARDLY OF SAID HOUSING, A TEMPERATURE-SENSITIVE INSTRUMENT MOUNTED IN SAID EXTENSION PORTION, A FUEL-AIR MIXER MOUNTED AT THE REAR OF SAID HOUSING WITH A FORWARD PORTION IN THE HOUSING AND INCLUDING TELESCOPING TUBULAR MEMBERS OPEN AT BOTH ENDS, A BRANCH CONDUIT FOR RECEIVING THE GASEOUS DISCHARGE OF THE EXTENSION PORTION AND CARRYING A FORWARDLY-DIRECTED DISCHARGE NOZZLE EXTENDING INTO THE REAR END OF THE TELESCOPING MEMBERS, AND MEANS INCLUDING A PRESSURE-ACTUATED MEMBER RESPONSIVE TO MEASURED TEMPERATURE VARIATIONS FOR CHANGING THE EFFECTIVE COMBINED LENGTH OF SAID TELESCOPING MEMBERS SO AS TO VARY FLAME IMPINGEMENT ON SAID COIL. 